#include<iostream>
#define no cout<<"No";return 0;
using namespace std;
int main(){
int a,b;
cin>>a>>b;
for(int i=0;i<a+b+1;i++){
char c;
cin>>c;
if(i==a){if(c!='-'){no;}}
else{if(c<'0'||'9'<c){no;}}
}
cout<<"Yes";
}