Let a,b and c denote the outcome of three independent rolls of a fair tetrahedral die, whose four faces are marked 1,2,3,4. If the probability that $a x^2+b x+c=0$ has all real roots is $\frac{m}{n}, \operatorname{gcd}(\mathrm{~m}, \mathrm{n})=1$ , then m+n is equal to
