#include <bits/stdc++.h>
using namespace std;
long long INF = 1LL << 60;
long long mod = 1e9 + 7;
int main() {
  int a, b;
  cin >> a >> b;
  string s;
  cin >> s;
  bool ok = true;
  for (long long i = 0; i < (long long)(a + b + 1); ++i) {
    if (i == a) {
      if (s[i] != '-') ok = false;
    } else {
      if ('0' <= s[i] && s[i] <= '9')
        ok = true;
      else
        ok = false;
    }
  }
  if (ok)
    cout << "Yes" << endl;
  else
    cout << "No" << endl;
}
