#include<bits/stdc++.h>
using namespace std;
int main(){
    int a,b,x=1;
    string s;
    cin>>a>>b>>s;
    for(int i=0;i<=a+b;i++){
        if((i<a||i>a)&&(s[i]>57||s[i]<48)) x=0;
        else if(i==a&&s[i]!='-') x=0;
    }
    if(x) cout<<"Yes"<<endl;
    else cout<<"No"<<endl;
}
