#include <bits/stdc++.h>
using namespace std;
int main() {
  int A, B, i, x = 0;
  string S;
  cin >> A >> B >> S;
  for (i = 0; i <= A + B; i++) {
    if (i == A) {
      if (S[i] == '-') {
        x++;
      }
    }
    if (i != A) {
      if (S[i] == '-') {
        cout << "No" << endl;
        x--;
        break;
      }
    }
  }
  if (S.size() == A + B + 1) {
    x++;
  }
  if (x == 2) {
    cout << "Yes" << endl;
  }
}
