CF273（D2）D DP

#include <map>
#include <set>
#include <cmath>
#include <ctime>
#include <queue>
#include <stack>
#include <cstdio>
#include <string>
#include <vector>
#include <cstring>
#include <sstream>
#include <iostream>
#include <algorithm>
#include <bitset>
#include <climits>
using namespace std;

#define wh while
#define inf (int)(~0u/2)
#define FOR(i, n) for(int i = 0; i < n; i++)
#define FOR1(i, n) for(int i = 1; i < n; i++)
#define FOR2(i, n) for(int i = 0; i <= n; i++)
#define REP(i,n) for(int i = 1; i <= n; i++)
#define FORI(it,n) for(typeof(n.begin()) it = n.begin(); it != n.end(); it++)
#define sf scanf
#define pf printf
#define frs first
#define sec second
#define psh push_back
#define mkp make_pair
#define PB(x) push_back(x)
#define MP(x, y) make_pair(x, y)
#define clr(abc,z) memset(abc,z,sizeof(abc))
#define lt(v) v << 1
#define rt(v) v << 1 | 1
//#define mid ((l + r) >> 1)
#define lson l, mid, v << 1
#define rson mid + 1, r, v << 1 | 1

#define fre freopen("1.txt", "r", stdin)

typedef long long LL;
typedef long double LD;

int N, M;
const int maxn = 2e5 + 100;
const int MOD = 1000000007;
int dp[maxn];

int main() {
    sf("%d%d", &N, &M);
    int h; for(h = 1; h * (h + 1) / 2 <= (N + M); h++); h--;
    dp[0] = 1;
    REP(i, h)
        for(int j = N - i; j >= 0; j--)
            dp[i + j] = (dp[i + j] + dp[j]) % MOD;
    h = (h + 1) * h / 2; int ans; ans = 0;
    for(int j = 0; j <= N; j++)
        if(h - j <= M) ans = (ans + dp[j]) % MOD;
    pf("%d\n", ans);
}