#include <iostream>
int main(){
int a, b; char c;
std::cin >> a >> c >> b;
if (15<a && a<20) std::cout << "20:02\n";
else if(5<a && a<10) std::cout << "10:01\n";
else if((a%10)*10+a/10>b) a/10==0 ? std::cout << 0 << a << ':' <<(a%10)*10+a/10<<'\n' : a%10!=0?std::cout << a <<':' <<(a%10)*10+a/10<<'\n':std::cout<<a<<':'<<0<<a/10<<"\n";
else{
++a;
if (15<a && a<20) std::cout << "20:02\n";
else if(5<a && a<10) std::cout << "10:01\n";
else a==24?std::cout<<"00:00\n":a/10==0?std::cout<<0<<a<<':'<<(a%10)*10+a/10<<'\n':std::cout<<a<<':'<<(a%10)*10+a/10<<'\n';
}
}
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