#include <bits/stdc++.h>
using namespace std;
int main() {
  int a, b;
  cin >> a >> b;
  string s;
  cin >> s;
  int f = 0;
  for (int i = 0; i < a + b + 1; i++) {
    if (i == a) {
      if (s[i] != '-') f = 0;
    } else {
      if (!isdigit(s[i])) f = 0;
    }
  }
  cout << (f ? "Yes" : "No") << endl;
}
