#include <bits/stdc++.h>
using namespace std;
#define rep(i, n) for (int i = 0; i < (int)(n); i++)
#define INF 1e9
#define PI 3.14159265359
#define MOD 1000000007
#define ALL(v) v.begin(),v.end()
#define ALLR(v) v.rbegin(),v.rend()
typedef long long ll;
const int dx[4] = {1,0,-1,0};
const int dy[4] = {0,1,0,-1};
//isPrime
//modpow modinv
//getDigit
int main() {
  cout << fixed << setprecision(10);
  int a,b;
  cin >> a >> b;
  string s;
  cin >> s;
  bool c = true;
  if(s.at(i)!='-'){
    c=false;
  }
  rep(i,a+b+1){
    if(i==a) continue;
    if(s.at(i)=='-'){
      c = false;
    }
  }
  if(c){
    cout << "Yes" << endl;
  }else{
    cout << "No" << endl;
  }
}
