#include <bits/stdc++.h>

typedef uint32_t u32;
typedef uint64_t u64;
typedef int32_t s32;
typedef int64_t s64;

s32 ri() {
	s32 n;
	scanf("%" SCNd32, &n);
	return n;
}
int main() {
#define int WHOOOO // 脱int訓練中につき許して
	s32 a = ri(), b = ri();
	s32 tmp = std::min(std::max(a, b) - 1, std::min(a, b));
	printf("%" PRId32 "\n", 2 * tmp);
	return 0;
}