#include <bits/stdc++.h>
using namespace std;
const long long mod = 1e9 + 7;
int main() {
  string s;
  long long a, b;
  scanf("%lld", &a);
  ;
  scanf("%lld", &b);
  ;
  cin >> s;
  long long i = 0;
  long long flag = 0;
  while (s[i] != '\0') {
    if (s[i] == '-' || s[i] == '0' || s[i] == '1' || s[i] == '2' ||
        s[i] == '3' || s[i] == '4' || s[i] == '5' || s[i] == '6' ||
        s[i] == '7' || s[i] == '8' || s[i] == '9') {
      flag = 1;
    } else {
      flag = 0;
      break;
    }
    i++;
  }
  if (flag == 1 && s[a] == '-') {
    cout << "Yes" << endl;
  } else {
    cout << "No" << endl;
  }
  return 0;
}
