local ffi = require 'ffi'
local M = ffi.load 'ssl'
ffi.cdef [[
typedef struct bignum_st {
	uint64_t *d;
	int top;
	int dmax;
	int neg;
	int flags;
} BN;
typedef BN * BN_ptr;
typedef const BN * BN_srcptr;
BN_ptr BN_new(void);
void BN_free(BN_ptr);
int BN_set_word(BN_ptr, uint64_t);
int BN_mul_word(BN_ptr, uint64_t);
char * BN_bn2dec(BN_srcptr);
void CRYPTO_free(void *, const char *, int);
]]

print((function (n)
	if n>=50 then return "000000000000" end
	local b=ffi.gc(M.BN_new(),M.BN_free)
	M.BN_set_word(b,1)
	for i=2,n do M.BN_mul_word(b,i+0ULL) end
	return ffi.string(ffi.gc(M.BN_bn2dec(b),function (a) M.CRYPTO_free(a,"",0) end)):sub(-12)
end)(io.stdin:read("*n")))