Connected graphs cospectral with a Friendship graph

Let n be any positive integer, the friendship graph fn consists of n edge-disjoint trianglesthat all of them meeting in one vertex. a graph g is called cospectral with a graph h if their adjacencymatrices have the same eigenvalues. recently in http://arxiv.org/pdf/1310.6529v1.pdf it is proved thatif g is any graph cospectral with fn (n 6= 16), then g = fn. here we give a proof of a special caseof the latter: any connected graph cospectral with fn is isomorphic to fn. our proof is independentof ones given in http://arxiv.org/pdf/1310.6529v1.pdf and the proofs are based on our recent resultsgiven in [trans. comb., 2 no. 4 (2013) 37-52.] using an upper bound for the largest eigenvalue of aconnected graph given in [j. combinatorial theory ser. b 81 (2001) 177-183.].