#include<bits/stdc++.h>
using namespace std;
const int N=1e5;
char s[N];
int main(){
int x,y;
cin>>x>>y;
cin>>s;

for(int i=0;i<x+y+1; ++i){
if(i==x){
if(s[i]!='-'){
cout<<"No\n";
return 0;
}
}
else{
 if(!(s[i]<='9' && s[i]>='0')){
    cout<<"No\n";
    return 0;
 }

 }

}
cout<<"Yes\n";
}
