In bioinformatics analysis, Expressed Sequence Tags (ESTs) are small pieces of expressed DNA sequences that provide scientists with a quick method for annotating genes in the genome. The idea is to use huge amount of ESTs as tags to fish genes out of the genome by aligning ESTs to the genome. The DNA segments with EST-aligning evidence are then annotated as putative genes. The annotation of genes using ESTs is challenging due to the false-positive mapping in the alignment results (e.g., one EST mapping to multiple genes). Ideally, each EST should be mapped to only one gene. However, the alignment of ESTs to the genome often generate multiple matches for one EST (or multiple ESTs mapped to the same gene). Given the alignment results of ESTs to genes in the genome, now you are asked to develop a system for annotating maximum number of genes. Note that each EST can be only mapped to at most one gene and vice versa. The system should report the maximum number of annotating genes under this requirement.

1. There are n ESTs and m genes, where 1 ≤ n, m ≤ 100.
2. The ESTs are denoted as {E₁, E₂, ..., E_n} 
3. The genes are denoted as {G₁, G₂, ..., G_m}. 
4. For each EST E_i, its matched genes G_j are given, where 1 ≤ i, j ≤ 100.