Probability for the Difference of Sample Means

The mean and standard deviation of daily caloric intake for Population 1 are $\mu_1 = 2200$ calories and $\sigma_1 = 400$ calories, respectively. For Population 2, the mean and standard deviation are $\mu_2 = 1900$ calories and $\sigma_2 = 350$ calories, respectively. Independent random samples of size $n_1 = 64$ and $n_2 = 49$ are taken from each population. What is the probability that the sample mean for Population 1 is at least 350 calories greater than the sample mean for Population 2?