10806

int main(){
    int n1,m;
    int a[maxn],b[maxn],c[maxn];
    while(scan(n1)!=EOF){
        if(n1==0)break;
        scan(m);
        rep(i,1,m){
            scannn(a[i],b[i],c[i]);
        }
        s=n1+1;t=s+1;n=t;
        rep(i,1,m){
            add(a[i],b[i],1,c[i]);
            add(b[i],a[i],1,c[i]);
        }
        add(s,1,2,0);add(n1,t,2,0);
        mcmf();
        if(mf<2)printf("Back to jail\n");
        else println(mc);
        
    }
}