#include <bits/stdc++.h>
using namespace std;
vector<unsigned long long int> vec;
vector<vector<unsigned long long int> > vec2;
unsigned long long int MOD = 1000000007;
unsigned long long int INF = 1145141919454519;
int main() {
  unsigned long long int A, B;
  string S;
  cin >> A >> B >> S;
  for (unsigned long long int i = 0; i < A + B + 1; i++) {
    if (i >= 0 && i < A || i >= B) {
      if (!(S[i] >= '0' && S[i] <= '9')) {
        cout << "No" << endl;
        return 0;
      }
    } else {
      if (S[i] != '-') {
        cout << "No" << endl;
        return 0;
      }
    }
  }
  cout << "Yes" << endl;
  return 0;
}
