#include<bits/stdc++.h>
#define ll long long
using namespace std;
int main() {
ios_base::sync_with_stdio(false);
cin.tie(NULL);
int t,l,i,j,p,k;
char s[50];
while(t--)
{
p=0;
cin>>s;
l=strlen(s);
for(i=0;i<l;i++)
{
k=-1;
if(s[i]!='.')
{
j=i+1;
while(j<l)
{
if(s[j]!=".")
{
k=j;
break;
}
j++;
}
}
if(k-i-1<(s[i]-48)+(s[k]-48))
{
p=1;
break;
}
}
if(p==1)
cout<<"unsafe"<<endl;
else
cout<<"unsafe"<<endl;
}
return 0;
}
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