#include <bits/stdc++.h>
using namespace std;
bool isNum(char i) {
  if ('0' <= i && i <= '9') return true;
}
int main(void) {
  int A, B;
  cin >> A >> B;
  string S;
  cin >> S;
  for (int i = 0; i < S.size(); i++) {
    if (i == A) {
      if (S[i] != '-') {
        cout << "No" << endl;
        return 0;
      }
    } else {
      if (!isNum(S[i])) {
        cout << "No" << endl;
        return 0;
      }
    }
  }
  cout << "Yes" << endl;
  return 0;
}
