scanf("%d", &a);
            for (int j = eul_dn[x].fir; j <= eul_dn[x].sec; ++ j) eul_val[j] += a;
            sum += ((eul_dn[x].sec-eul_dn[x].fir+1)>>1)*a;

            scanf("%d", &a);
            ll qk = 0;
            for (int j = eul_dn[x].fir; j <= eul_dn[x].sec; ++ j) qk += a, eul_val[j] += a;
            sum += qk>>1;