//package global001;
import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.util.Arrays;
import java.util.Comparator;
import java.util.InputMismatchException;
import java.util.Random;

public class F {
	InputStream is;
	PrintWriter out;
	String INPUT = "";
	
	void solve()
	{
		int n = ni(), Q = ni();
		int[] from = new int[n - 1];
		int[] to = new int[n - 1];
		int[] ws = new int[n-1];
		for (int i = 0; i < n-1; i++) {
			from[i] = i+1;
			to[i] = ni() - 1;
			ws[i] = ni();
		}
		int[][][] g = packWU(n, from, to, ws);
//		int[][] pg = packU(n, from, to);
//		Random gen = new Random();
//		for(int[] row : pg){
//			Arrays.sort(shuffle(row, gen));
//		}
		int[][] pars = parents(g, 0);
		int[] par = pars[0], dep = pars[2], pw = pars[4];
		int[][] qs = new int[Q][];
		for(int i = 0;i < Q;i++){
			qs[i] = new int[]{ni()-1, ni()-1, ni()-1, i};
		}
		long[] dw = new long[n];
		for(int i = 1;i < n;i++){
			dw[i] = dw[par[i]] + pw[i];
		}
		long[] ins = Arrays.copyOf(dw, n);
		for(int i = 0;i < n;i++){
			if(g[i].length != 1){
				ins[i] = Long.MAX_VALUE / 10;
			}
		}
		
		int[] right = new int[n];
		Arrays.fill(right, n);
		for(int i = 0;i < n-1;i++){
			int x = i;
			while(x != par[i+1]){
				right[x] = i+1;
				x = par[x];
			}
		}
		
		Arrays.sort(qs, new Comparator<int[]>() {
			public int compare(int[] a, int[] b) {
				return a[0] - b[0];
			}
		});
		StarrySkyTreeL sst = new StarrySkyTreeL(ins);
		int p = 0;
		long[] anss = new long[Q];
		for(int i = 0;i < n;i++){
			while(p < Q && qs[p][0] == i){
				anss[qs[p][3]] = sst.min(qs[p][1], qs[p][2]+1) + dw[qs[p][0]];
				p++;
			}
			// i -> i+1
			if(i < n-1){
				int x = i;
				while(x != par[i+1]){
					sst.add(x, right[x], 2L*pw[x]);
					x = par[x];
				}
				sst.add(i+1, right[i+1], -2L*pw[i+1]);
			}
		}
		for(long v : anss){
			out.println(v);
		}
	}
	
	public static int[] shuffle(int[] a, Random gen){ for(int i = 0, n = a.length;i < n;i++){ int ind = gen.nextInt(n-i)+i; int d = a[i]; a[i] = a[ind]; a[ind] = d; } return a; }

	
	static int[][] packU(int n, int[] from, int[] to) {
		int[][] g = new int[n][];
		int[] p = new int[n];
		for (int f : from)
			p[f]++;
		for (int t : to)
			p[t]++;
		for (int i = 0; i < n; i++)
			g[i] = new int[p[i]];
		for (int i = 0; i < from.length; i++) {
			g[from[i]][--p[from[i]]] = to[i];
			g[to[i]][--p[to[i]]] = from[i];
		}
		return g;
	}
	
	public static class StarrySkyTreeL {
		public int M, H, N;
		public long[] st;
		public long[] plus;
		public long I = Long.MAX_VALUE/4; // I+plus<long
		
		public StarrySkyTreeL(int n)
		{
			N = n;
			M = Integer.highestOneBit(Math.max(n-1, 1))<<2;
			H = M>>>1;
			st = new long[M];
			plus = new long[H];
		}
		
		public StarrySkyTreeL(long[] a)
		{
			N = a.length;
			M = Integer.highestOneBit(Math.max(N-1, 1))<<2;
			H = M>>>1;
			st = new long[M];
			for(int i = 0;i < N;i++){
				st[H+i] = a[i];
			}
			plus = new long[H];
			Arrays.fill(st, H+N, M, I);
			for(int i = H-1;i >= 1;i--)propagate(i);
		}
		
		private void propagate(int i)
		{
			st[i] = Math.min(st[2*i], st[2*i+1]) + plus[i];
		}
		
		public void add(int l, int r, long v){ if(l < r)add(l, r, v, 0, H, 1); }
		
		private void add(int l, int r, long v, int cl, int cr, int cur)
		{
			if(l <= cl && cr <= r){
				if(cur >= H){
					st[cur] += v;
				}else{
					plus[cur] += v;
					propagate(cur);
				}
			}else{
				int mid = cl+cr>>>1;
				if(cl < r && l < mid){
					add(l, r, v, cl, mid, 2*cur);
				}
				if(mid < r && l < cr){
					add(l, r, v, mid, cr, 2*cur+1);
				}
				propagate(cur);
			}
		}
		
		public long min(int l, int r){ return l >= r ? I : min(l, r, 0, H, 1);}
		
		private long min(int l, int r, int cl, int cr, int cur)
		{
			if(l <= cl && cr <= r){
				return st[cur];
			}else{
				int mid = cl+cr>>>1;
				long ret = I;
				if(cl < r && l < mid){
					ret = Math.min(ret, min(l, r, cl, mid, 2*cur));
				}
				if(mid < r && l < cr){
					ret = Math.min(ret, min(l, r, mid, cr, 2*cur+1));
				}
				return ret + plus[cur];
			}
		}
		
		public void fall(int i)
		{
			if(i < H){
				if(2*i < H){
					plus[2*i] += plus[i];
					plus[2*i+1] += plus[i];
				}
				st[2*i] += plus[i];
				st[2*i+1] += plus[i];
				plus[i] = 0;
			}
		}
		
		public int firstle(int l, long v) {
			int cur = H+l;
			for(int i = 1, j = Integer.numberOfTrailingZeros(H)-1;i <= cur;j--){
				fall(i);
				i = i*2|cur>>>j&1;
			}
			while(true){
				fall(cur);
				if(st[cur] <= v){
					if(cur < H){
						cur = 2*cur;
					}else{
						return cur-H;
					}
				}else{
					cur++;
					if((cur&cur-1) == 0)return -1;
					cur = cur>>>Integer.numberOfTrailingZeros(cur);
				}
			}
		}
		
		public int lastle(int l, long v) {
			int cur = H+l;
			for(int i = 1, j = Integer.numberOfTrailingZeros(H)-1;i <= cur;j--){
				fall(i);
				i = i*2|cur>>>j&1;
			}
			while(true){
				fall(cur);
				if(st[cur] <= v){
					if(cur < H){
						cur = 2*cur+1;
					}else{
						return cur-H;
					}
				}else{
					if((cur&cur-1) == 0)return -1;
					cur = cur>>>Integer.numberOfTrailingZeros(cur);
					cur--;
				}
			}
		}
		
		public void addx(int l, int r, long v){
			if(l >= r)return;
			while(l != 0){
				int f = l&-l;
				if(l+f > r)break;
				if(f == 1){
					st[(H+l)/f] += v;
				}else{
					plus[(H+l)/f] += v;
				}
				l += f;
			}
			
			while(l < r){
				int f = r&-r;
				if(f == 1){
					st[(H+r)/f-1] += v;
				}else{
					plus[(H+r)/f-1] += v;
				}
				r -= f;
			}
		}
		
		public long minx(int l, int r){
			long lmin = I;
			if(l >= r)return lmin;
			if(l != 0){
				for(int d = 0;H>>>d > 0;d++){
					if(d > 0){
						int id = (H+l-1>>>d);
						lmin += plus[id];
					}
					if(l<<~d<0 && l+(1<<d) <= r){
						long v = st[H+l>>>d];
						if(v < lmin)lmin = v;
						l += 1<<d;
					}
				}
			}
			long rmin = I;
			for(int d = 0;H>>>d > 0;d++){
				if(d > 0 && r < H)rmin += plus[H+r>>>d];
				if(r<<~d<0 && l < r){
					long v = st[(H+r>>>d)-1];
					if(v < rmin)rmin = v;
					r -= 1<<d;
				}
			}
			long min = Math.min(lmin, rmin);
			return min;
		}
		
		public long[] toArray() { return toArray(1, 0, H, new long[H]); }
		
		private long[] toArray(int cur, int l, int r, long[] ret)
		{
			if(r-l == 1){
				ret[cur-H] = st[cur];
			}else{
				toArray(2*cur, l, l+r>>>1, ret);
				toArray(2*cur+1, l+r>>>1, r, ret);
				for(int i = l;i < r;i++)ret[i] += plus[cur];
			}
			return ret;
		}
	}

	
	public static int[][] parents(int[][][] g, int root) {
		int n = g.length;
		int[] par = new int[n];
		Arrays.fill(par, -1);
		int[] dw = new int[n];
		int[] pw = new int[n];
		int[] dep = new int[n];

		int[] q = new int[n];
		q[0] = root;
		for (int p = 0, r = 1; p < r; p++) {
			int cur = q[p];
			for (int[] nex : g[cur]) {
				if (par[cur] != nex[0]) {
					q[r++] = nex[0];
					par[nex[0]] = cur;
					dep[nex[0]] = dep[cur] + 1;
					dw[nex[0]] = dw[cur] + nex[1];
					pw[nex[0]] = nex[1];
				}
			}
		}
		return new int[][] { par, q, dep, dw, pw };
	}

	
	public static int[][][] packWU(int n, int[] from, int[] to, int[] w) {
		int[][][] g = new int[n][][];
		int[] p = new int[n];
		for (int f : from)
			p[f]++;
		for (int t : to)
			p[t]++;
		for (int i = 0; i < n; i++)
			g[i] = new int[p[i]][2];
		for (int i = 0; i < from.length; i++) {
			--p[from[i]];
			g[from[i]][p[from[i]]][0] = to[i];
			g[from[i]][p[from[i]]][1] = w[i];
			--p[to[i]];
			g[to[i]][p[to[i]]][0] = from[i];
			g[to[i]][p[to[i]]][1] = w[i];
		}
		return g;
	}


	
	void run() throws Exception
	{
		is = oj ? System.in : new ByteArrayInputStream(INPUT.getBytes());
		out = new PrintWriter(System.out);
		
		long s = System.currentTimeMillis();
		solve();
		out.flush();
		tr(System.currentTimeMillis()-s+"ms");
	}
	
	public static void main(String[] args) throws Exception { new F().run(); }
	
	private byte[] inbuf = new byte[1024];
	public int lenbuf = 0, ptrbuf = 0;
	
	private int readByte()
	{
		if(lenbuf == -1)throw new InputMismatchException();
		if(ptrbuf >= lenbuf){
			ptrbuf = 0;
			try { lenbuf = is.read(inbuf); } catch (IOException e) { throw new InputMismatchException(); }
			if(lenbuf <= 0)return -1;
		}
		return inbuf[ptrbuf++];
	}
	
	private boolean isSpaceChar(int c) { return !(c >= 33 && c <= 126); }
	private int skip() { int b; while((b = readByte()) != -1 && isSpaceChar(b)); return b; }
	
	private double nd() { return Double.parseDouble(ns()); }
	private char nc() { return (char)skip(); }
	
	private String ns()
	{
		int b = skip();
		StringBuilder sb = new StringBuilder();
		while(!(isSpaceChar(b))){ // when nextLine, (isSpaceChar(b) && b != ' ')
			sb.appendCodePoint(b);
			b = readByte();
		}
		return sb.toString();
	}
	
	private char[] ns(int n)
	{
		char[] buf = new char[n];
		int b = skip(), p = 0;
		while(p < n && !(isSpaceChar(b))){
			buf[p++] = (char)b;
			b = readByte();
		}
		return n == p ? buf : Arrays.copyOf(buf, p);
	}
	
	private char[][] nm(int n, int m)
	{
		char[][] map = new char[n][];
		for(int i = 0;i < n;i++)map[i] = ns(m);
		return map;
	}
	
	private int[] na(int n)
	{
		int[] a = new int[n];
		for(int i = 0;i < n;i++)a[i] = ni();
		return a;
	}
	
	private int ni()
	{
		int num = 0, b;
		boolean minus = false;
		while((b = readByte()) != -1 && !((b >= '0' && b <= '9') || b == '-'));
		if(b == '-'){
			minus = true;
			b = readByte();
		}
		
		while(true){
			if(b >= '0' && b <= '9'){
				num = num * 10 + (b - '0');
			}else{
				return minus ? -num : num;
			}
			b = readByte();
		}
	}
	
	private long nl()
	{
		long num = 0;
		int b;
		boolean minus = false;
		while((b = readByte()) != -1 && !((b >= '0' && b <= '9') || b == '-'));
		if(b == '-'){
			minus = true;
			b = readByte();
		}
		
		while(true){
			if(b >= '0' && b <= '9'){
				num = num * 10 + (b - '0');
			}else{
				return minus ? -num : num;
			}
			b = readByte();
		}
	}
	
	private boolean oj = System.getProperty("ONLINE_JUDGE") != null;
	private void tr(Object... o) { if(!oj)System.out.println(Arrays.deepToString(o)); }
}
