Const Fi='GIAITHUA.INP';
Fo='GIAITHUA.OUT';
Var f,g: text;
n: longint;
Function GT(a: byte): qword;
Begin
If (m=0) or (m=1) then GT:=1;
Else
GT:=a*GT(a-1);
End;
Begin
Assign(f,Fi); Reset(f);
Assign(g,Fo); Rewrite(g);
Read(f,n);
Write(g,GT(n));
Close(f);
Close(g);
End.