#include <cstdio>
#define ui unsigned int

inline ui nrzero(ui i)
{
ui t=0;
while(i) t+=i/=5;
return t;
}

int main()
{
ui cnt, n, i, p, q;

freopen("fact.in","r",stdin);
freopen("fact.out","w",stdout);
scanf("%d", &n);

for(i=cnt=1<<30;cnt;cnt>>=1)
i-=i-cnt>=1 && nrzero(i-cnt)>=n ?cnt:0; // if(i-cnt>=1 && nrzero(i-cnt)>=n) i-=cnt;
i=nrzero(i)==n?i:-1;
printf("%d\n", i);
return 0;
}