#include <bits/stdc++.h>
using namespace std;
constexpr auto INF = 1000000000;
constexpr auto mod = 1000000007;
int ni(int n) {
  if (n == 0) return 1;
  int x = ni(n / 2);
  x *= x;
  if (n % 2 == 1) x *= 2;
  return x;
}
long long int f(int x, vector<long long int>& s) {
  if (x == 0) return 0;
  if (x == 1) return 1;
  if (s[x] != 0) return s[x];
  return s[x] = f(x - 1, s) + f(x - 2, s);
}
long long int gcd(long long int a, long long int b) {
  if (a < b) swap(a, b);
  if (b == 0) return a;
  return gcd(b, a % b);
}
long long modpow(long long a, long long n, long long mod) {
  long long res = 1;
  while (n > 0) {
    if (n & 1) res = res * a % mod;
    a = a * a % mod;
    n >>= 1;
  }
  return res;
}
long long modinv(long long a, long long m) {
  long long b = m, u = 1, v = 0;
  while (b) {
    long long t = a / b;
    a -= t * b;
    swap(a, b);
    u -= t * v;
    swap(u, v);
  }
  u %= m;
  if (u < 0) u += m;
  return u;
}
long long int c(long long int a, long long int b, long long int m) {
  long long int ans = 1;
  for (long long int i = 0; i < b; i++) {
    ans *= a - i;
    ans %= m;
  }
  for (long long int i = 1; i <= b; i++) {
    ans *= modinv(i, m);
    ans %= m;
  }
  return ans;
}
void dfs(int m, int n, long long int k, vector<long long int> a) {
  stack<string> st;
  st.push("");
  while (!st.empty()) {
    string now = st.top();
    st.pop();
    if (now.size() == n) {
      cout << now << endl;
    } else {
      for (int i = m - 1; i >= 0; i--) {
        string next = now + to_string(i);
        st.push(next);
      }
    }
  }
}
void press(vector<int>& v) { v.erase(unique((v).begin(), (v).end()), v.end()); }
void press(vector<char>& v) {
  v.erase(unique((v).begin(), (v).end()), v.end());
}
struct UnionFind {
  vector<int> par;
  UnionFind(int N) : par(N) {
    for (int i = 0; i < N; i++) par[i] = i;
  }
  int size(int a) { return par[root(a)]; }
  int root(int x) {
    if (par[x] == x) return x;
    return par[x] = root(par[x]);
  }
  void unite(int x, int y) {
    int rx = root(x);
    int ry = root(y);
    if (rx == ry) return;
    par[rx] = ry;
  }
  bool same(int x, int y) {
    int rx = root(x);
    int ry = root(y);
    return rx == ry;
  }
};
struct segmenttree {
  vector<int> seg;
  int s;
  segmenttree(int n) : seg(n * 2 - 1) {
    for (int i = 0; i < n * 2 - 1; i++) seg[i] = 0;
    s = n;
  }
  void update(int k, int a) {
    k += s - 1;
    seg[k] += a;
    while (k > 0) {
      k = (k - 1) / 2;
      seg[k] = min(seg[k * 2 + 1], seg[k * 2 + 2]);
    }
  }
  int query(int a, int b, int k, int l, int r) {
    if (r <= a || b <= l) return 1000000;
    if (a <= l && r <= b)
      return seg[k];
    else {
      int v1 = query(a, b, k * 2 + 1, l, (l + r) / 2);
      int v2 = query(a, b, k * 2 + 2, (l + r) / 2, r);
      return min(v1, v2);
    }
  }
};
int main() {
  int a, b;
  cin >> a >> b;
  string s;
  cin >> s;
  bool ans = true;
  for (int i = (0); i < (a + b + 1); i++) {
    if (s[a] != '-') ans = false;
    if (i != a && i == '-') ans = false;
  }
  if (ans)
    cout << "Yes" << endl;
  else
    cout << "No" << endl;
  return 0;
}
