down to 202 digits...
(m-378)=[97, 1; 433, 1; 16934441, 1; 703270816301, 1; 7418500016177, 1; 3117458348798567, 1; 167504463553356229, 1; 212277134215262027, 1]
       * P222
P222 a 222-digit prime, and 
where P222-1 = [2, 3; 307, 1; 367, 1; 1327, 1; 117448071163, 1] * 
            C202
      C202 = 2447032325560455619090080400966841332396348589865051791622199967430749799654440653044823303321712773304736305741579172454744607203231860797899132226780682801111397987736983185475040828099534808700359239

(gmp ecm searched to B1=508540 with -I 1)