scanf("%d%d", &n, &m);

for(int i = 1; i<=m; i++)

scanf("%d%d%d", &a[i].l, &a[i].p, &a[i].s);

sort(a+1, a+m+1, cmp);

for(int i = 1; i<=m; i++){

le[i] = max(0, a[i].s-a[i].l); //求出左边界

re[i] = min(n, a[i].s+a[i].l-1); //求出右边界

}

int i, j, l, p, s, h, t;

for(i = 1; i<=m; i++){

l = a[i].l;

p = a[i].p;

s = a[i].s;

for(j = 0; j<=re[i]; j++)

dp[i][j] = dp[i-1][j]; //先转移第i个人不刷

h = 1; t = 0;

for(j = le[i]; j<a[i].s; j++){ //维护单调队列

while(h<=t&&dp[i-1][j]-j*p>=dp[i-1][q[t]]-q[t]*p) t--;

q[++t] = j;

}

for(j = s; j<=re[i]; j++){

while(h<t&&j-q[h]>l) h++; //若不符合就pop

dp[i][j] = max(dp[i][j-1], dp[i-1][j]);

dp[i][j] = max(dp[i][j], dp[i-1][q[h]]+(j-q[h])*p);

}

for(j = re[i]+1; j<=n; j++)

dp[i][j] = max(dp[i-1][j], dp[i][j-1]);

}

int ans = 0;

for(int i = 1; i<=n; i++)

ans = max(ans, dp[m][i]);

printf("%d\n", ans);

read();

work();

return 0;

}