代码

#pragma GCC optimize("Ofast,unroll-loops")
#include <stdio.h>
#include <ctype.h>

char _I_Buffer[26],_O_Buffer[26],*_I_pos = _I_Buffer,*_O_pos = _O_Buffer;
inline int get()
{
	register int res = 0;
	register bool k = 1;
	while (!isdigit(*_I_pos))
		if (*_I_pos++ == '-')k = 0;
	do res = (res << 3) + (res << 1), res += (*_I_pos++) & 15;while (isdigit(*_I_pos));
	return k ? res : -res;
}
inline void put(register long long n)
{
	static char _buf[20];
	register char* _pos(_buf);
	if (n < 0) {*_O_pos++ = '-';n = -n;}
	do *_pos++ = 48 + n % 10;while (n /= 10);
	while (_pos != _buf)*_O_pos++ = *--_pos;
}
int main()
{
	fread(_I_Buffer, 1, 26, stdin);
	register int a = get(),b = get();
	put(1ll*a*b-a-b);
	fwrite(_O_Buffer, 1, _O_pos - _O_Buffer, stdout);
}

评测结果