In solving the Travelling Salesman Problem (TSP) to find an optimal tour connecting 20 cities, a Genetic Algorithm (GA) maintains a constant population size of 1200 across each generation. In addition to elitism selection of size 2, the GA also implements a 3-way tournament selection strategy - in both cases, selection does not remove candidates from the population. Mating pool members (parents) form pairs for subsequent crossover operations, where each pair produces exactly one (no more & no less) offspring and each member belongs to exactly one (no more & no less) pair. How many 3-way tournaments must run each generation in order that the population is replenished in the next?