#include <bits/stdc++.h>
using namespace std;
const int EPS = 1e-9;
int main() {
  cin.tie(0);
  ios::sync_with_stdio(false);
  int a, b;
  string s;
  while (cin >> a >> b >> s) {
    int cnt = 0;
    bool ans = true;
    while (cnt < a) {
      if (s[cnt] - '0' < 0 || s[cnt] - '0' > 9) ans = false;
      cnt++;
    }
    if (s[cnt] != '-') ans = false;
    cnt++;
    while (cnt < b + 1) {
      if (s[cnt] - '0' < 0 || s[cnt] - '0' > 9) ans = false;
      cnt++;
    }
    if (s.size() != a + b + 1) ans = false;
    if (ans)
      cout << "Yes" << endl;
    else
      cout << "No" << endl;
  }
  return 0;
}
