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