#include <bits/stdc++.h>

#ifndef ONLINE_JUDGE
#define gc getchar()
#define pc(c) putchar(c)
#else
#define gc getchar_unlocked()
#define pc(c) putchar_unlocked(c)
#endif

#define MOD 1000000007
#define inf 2000000000
#define fill(array, value) memset(array, value, sizeof(array));
#define long long long
using namespace std;

static struct IO
{
	char tmp[1 << 10];

	// fast input routines
	char cur;

	inline char nextChar() { return cur = gc; }
	inline char peekChar() { return cur; }

	inline operator bool() { return peekChar(); }
	inline static bool isBlank(char c) { return (c < '-' && c); }
	inline bool skipBlanks() { while (isBlank(nextChar())); return peekChar() != 0; }

	inline IO& operator >> (char & c) { c = nextChar(); return *this; }

	inline IO& operator >> (char * buf) {
		if (skipBlanks()) {
			if (peekChar()) {
				*(buf++) = peekChar();
				while (!isBlank(nextChar())) *(buf++) = peekChar();
			} *(buf++) = 0; } return *this; }

	inline IO& operator >> (string & s) {
		if (skipBlanks()) {	s.clear(); s += peekChar();
			while (!isBlank(nextChar())) s += peekChar(); }
		return *this; }

	inline IO& operator >> (double & d) { if ((*this) >> tmp) sscanf(tmp, "%lf", &d); return *this;	}

#define defineInFor(intType) \
	inline IO& operator >>(intType & n) { \
		if (skipBlanks()) { \
			int sign = +1; \
			if (peekChar() == '-') { \
				sign = -1; \
				n = nextChar() - '0'; \
			} else \
				n = peekChar() - '0'; \
			while (!isBlank(nextChar())) { \
				n += n + (n << 3) + peekChar() - 48; \
			} \
			n *= sign; \
		} \
		return *this; \
	}

defineInFor(int)
defineInFor(unsigned int)
defineInFor(long)

	// fast output routines

	inline void putChar(char c) { pc(c); }
	inline IO& operator << (char c) { putChar(c); return *this; }
	inline IO& operator << (const char * s) { while (*s) putChar(*s++); return *this; }

	inline IO& operator << (const string & s) { for (int i = 0; i < (int)s.size(); ++i) putChar(s[i]); return *this; }

	char * toString(double d) { sprintf(tmp, "%lf%c", d, '\0'); return tmp; }
	inline IO& operator << (double d) { return (*this) << toString(d); }

#define defineOutFor(intType) \
	inline char * toString(intType n) { \
		char * p = (tmp + 30); \
		if (n) { \
			bool isNeg = 0; \
			if (n < 0) isNeg = 1, n = -n; \
			while (n) \
				*--p = (n % 10) + '0', n /= 10; \
			if (isNeg) *--p = '-'; \
		} else *--p = '0'; \
		return p; \
	} \
	inline IO& operator << (intType n) { return (*this) << toString(n); }

defineOutFor(int)
defineOutFor(long)

#define endl ('\n')
#define cout __io__
#define cin __io__
} __io__;

int main()
{
	long m,n;
	cin >> m >> n;
	cout << m*n-1;
	return 0;
}