#include <bits/stdc++.h>
using namespace std;
int main() {
  int A, B;
  string S;
  cin >> A >> B;
  cin >> S;
  bool is_correct = true;
  if (A + B + 1 != (int)S.size()) {
    is_correct = false;
  }
  if (S.at(A) != '-') {
    is_correct = false;
  }
  for (int i = 0; i < (int)S.size(); i++) {
    if (S.at(i) >= '0' && S.at(i) <= '9') {
      continue;
    } else {
      is_correct = false;
      break;
    }
  }
  if (is_correct) {
    cout << "Yes" << endl;
  } else {
    cout << "No" << endl;
  }
  return 0;
}
