1+1+97=99; 1+2+96=99; 1+3+95, 1+4+94, ..., 1+48+50, 1+49+49, (49 ways)
2+2+95, 2+3+94, 2+4+93, ..., 2+47+50, 2+48+49, (47 ways)
3+3+93, 3+4+92, ..., 3+46+50, 3+47+49, 3+48+48, (46 ways)
4+4+91, 4+5+90, ..., 4+47+48 (44 ways)
5+5+89, 5+6+88, ..., 5+47+47 (43 ways)
...,
30+30+39, 30+31+38, 30+32+37, 30+33+36, 30+34+35, (5 ways)
31+31+37, 31+32+36, 31+33+35, 31+34+34, (4 ways)
32+32+35, 32+33+34 (2 ways)
33+33+33 (1 way)
TOTAL: 1+2+4+5+7+8+10+11+...+49=49*50/2 - 3(1+2+3+...+16)=1225-3*16*17/2=1225-408=817.