import java.util.*;

public class Main {
	Scanner sc = new Scanner(System.in);

	void doIt() {
		int a = sc.nextInt();
		int b = sc.nextInt();
		int t = sc.nextInt();
		int next = 0, cnt = -b, i = 1;
		while(next <= t) {
			next += a * i;
			cnt+= b;
		}
		System.out.println(cnt);
		
	}
	
	public static void main(String[] args) {
		new Main().doIt();
	}
} import java.util.*; util.* java public class Main {
	Scanner sc = new Scanner(System.in);

	void doIt() {
		int a = sc.nextInt();
		int b = sc.nextInt();
		int t = sc.nextInt();
		int next = 0, cnt = -b, i = 1;
		while(next <= t) {
			next += a * i;
			cnt+= b;
		}
		System.out.println(cnt);
		
	}
	
	public static void main(String[] args) {
		new Main().doIt();
	}
} Main Scanner sc = new Scanner(System.in); sc new Scanner(System.in) void doIt() {
		int a = sc.nextInt();
		int b = sc.nextInt();
		int t = sc.nextInt();
		int next = 0, cnt = -b, i = 1;
		while(next <= t) {
			next += a * i;
			cnt+= b;
		}
		System.out.println(cnt);
		
	} doIt {
		int a = sc.nextInt();
		int b = sc.nextInt();
		int t = sc.nextInt();
		int next = 0, cnt = -b, i = 1;
		while(next <= t) {
			next += a * i;
			cnt+= b;
		}
		System.out.println(cnt);
		
	} int a = sc.nextInt(); a sc.nextInt() sc.nextInt sc int b = sc.nextInt(); b sc.nextInt() sc.nextInt sc int t = sc.nextInt(); t sc.nextInt() sc.nextInt sc int next = 0 next 0 cnt = -b cnt -b b i = 1; i 1 while(next <= t) {
			next += a * i;
			cnt+= b;
		} next <= t next t {
			next += a * i;
			cnt+= b;
		} next += a * i next a * i a i cnt+= b cnt b System.out.println(cnt) System.out.println System.out System System.out cnt public static void main(String[] args) {
		new Main().doIt();
	} main {
		new Main().doIt();
	} new Main().doIt() new Main().doIt new Main() String[] args args public class Main {
	Scanner sc = new Scanner(System.in);

	void doIt() {
		int a = sc.nextInt();
		int b = sc.nextInt();
		int t = sc.nextInt();
		int next = 0, cnt = -b, i = 1;
		while(next <= t) {
			next += a * i;
			cnt+= b;
		}
		System.out.println(cnt);
		
	}
	
	public static void main(String[] args) {
		new Main().doIt();
	}
} public class Main {
	Scanner sc = new Scanner(System.in);

	void doIt() {
		int a = sc.nextInt();
		int b = sc.nextInt();
		int t = sc.nextInt();
		int next = 0, cnt = -b, i = 1;
		while(next <= t) {
			next += a * i;
			cnt+= b;
		}
		System.out.println(cnt);
		
	}
	
	public static void main(String[] args) {
		new Main().doIt();
	}
} Main
import java.util.*;

public class Main {
	Scanner sc = new Scanner(System.in);

	void doIt() {
		int a = sc.nextInt();
		int b = sc.nextInt();
		int t = sc.nextInt();
		int next = 0, cnt = -b, i = 1;
		while(next <= t) {
			next += a * i;
			cnt+= b;
		}
		System.out.println(cnt);
		
	}
	
	public static void main(String[] args) {
		new Main().doIt();
	}
}
