#include <bits/stdc++.h>
using namespace std;
template <class T>
inline bool chMax(T& a, T b) {
  if (a < b) {
    a = b;
    return true;
  }
  return false;
}
template <class T>
inline bool chMin(T& a, T b) {
  if (a > b) {
    a = b;
    return true;
  }
  return false;
}
int main() {
  long long A, B;
  string S;
  cin >> A >> B >> S;
  if (S[A] != '-') {
    cout << "No" << endl;
    return 0;
  }
  S.erase(A, 1);
  try {
    long long temp = stoi(S, nullptr, 10);
  } catch (...) {
    cout << "No" << endl;
    return 0;
  }
  cout << "Yes" << endl;
  return 0;
}
