Compilare: main.cpp:1:2: warning: #import is a deprecated GCC extension [-Wdeprecated] #import<fstream> ^~~~~~ main.cpp:2:18: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type] int p,m,s,n;main(){std::ifstream{"fact.in"}>>p;for(n=4*p;s<p;n++)for(m=n,s=0;m;s+=m/=5);std::ofstream{"fact.out"}<<(s-p?-1:p?n-1:1);} ^