#include <bits/stdc++.h>
using namespace std;
int main() {
  int a, b;
  char s[256];
  cin >> a >> b;
  cin >> s;
  int i;
  bool ans = true;
  for (i = 0; i < a + b + 1; i++) {
    if (i == a) {
      if (s[i] != '-') {
        ans = false;
      }
    } else {
      if (s[i] < '0' && s[i] > '9') {
        ans = false;
      }
    }
  }
  if (ans)
    cout << "Yes" << endl;
  else
    cout << "No" << endl;
  return 0;
}
