#include <bits/stdc++.h>
using namespace std;
int main() {
  int A, B;
  int flag1 = 0;
  int flag2 = 0;
  cin >> A >> B;
  string s;
  cin >> s;
  if (s[A] != '-') {
    cout << "No" << endl;
  } else {
    for (int i = 0; i < A; i++) {
      if (0 > s[i] || s[i] > 9) {
        flag1 = 1;
      }
    }
    for (int i = A + 1; i < A + B + 2; i++) {
      if (0 > s[i] || s[i] > 9) {
        flag2 = 1;
      }
    }
  }
  if (flag1 == 1 || flag2 == 1) {
    cout << "No" << endl;
  } else {
    cout << "Yes" << endl;
  }
  flag1 = 0;
  flag2 = 0;
}
