#include <bits/stdc++.h>
using namespace std;

int main() {
  int a,b;cin>>a>>b;
  string s;cin>>s;
  bool ok=true;
  for(int i=0;i<s.size();++i){
    if(i==a) ok &= (s[i]=='-');
    else ok &= ('0'<=s[i] && s[i]<='9');
  }
  cout<<(ok?"Yes":"No")<<endl;
}