By Sarah N. Lynch WASHINGTON (Reuters) - International Monetary Fund Managing Director Christine Lagarde said Sunday she is disappointed with the inconclusive outcome of talks with Greece, which is teetering on the brink of a default on its debt to the IMF. At the same time, Lagarde said she is still willing to continue talks with the Greek government in the hope the country can make "appropriate structural and fiscal reforms" that are supported by "financing and debt sustainability measures." "I continue to believe that a balanced approach is required to help restore economic stability and growth in Greece," she said.