Help:=proc():print(`Ruin(L)`):end: Ruin:=proc(L) local eq,var,r,i: var:={seq(r[i],i=0..L)}: eq:={r[0]=0,r[L]=0, seq(r[i]=1/2*(r[i-1]+r[i+1])+1,i=1..L-1)}: subs(solve(eq,var),[seq(r[i],i=1..L-1)]): end: